PVC food packaging wrap has been increasingly widely used for packaging fresh food as the importance of supermarkets in the retail business grows. The use of PVC food packaging wrap in homes has also increased with the increase in the use of refrigerators and microwave ovens for preserving and cooking food. The PVC food packaging wrap for such applications are required to have a clinging property for the convenience of wrapping food items, a freshness preserving property based on a suitable degree of air permeability, an anti-fogging property, and transparency.
The known methods for giving an anti-bacterial property to organic high polymer film include the method of dispersing an anti-bacterial inorganic compound in an organic high polymer, and forming the high polymer into film, and the method of applying an anti-bacterial inorganic compound over the surface of organic high polymer film. Known anti-bacterial inorganic compounds include those carrying anti-bacterial ions in zeolite and aluminosilicate.
In the field of food packaging wrap, it is known to use an anti-bacterial compound consisting of zeolite or aluminosilicate carrying anti-bacterial ions to obtain an anti-bacterial property, and to disperse this compound in an organic high polymer which is then formed into film.
However, according to such conventional granular anti-bacterial compounds or compositions, because they do not readily disperse, and can therefore impair the clinging property, transparency and anti-fogging property of the film, the film could lose its property to cling to and wrap around the food items, and the commercial value of the food items could be damaged by failing to show the favorable appearance of the food items through the film when displaying the food items in retail stores so that the film may be considered unsatisfactory for wrapping food items.
Also, when an anti-bacterial compound is added to PVC, the chloride which is released from the resin during the thermal molding process combines with silver and other metallic ions, which are effective in repelling bacteria, and produces water-insoluble silver chloride. Such consumption of the anti-bacterial component severely reduces the anti-bacterial property of the film.
It is possible to add an excess amount of an anti-bacterial compound in the film to offset the consumption of the anti-bacterial compound during the molding process. However, if the anti-bacterial compound is added by such an excess amount, it could ruin the properties of the film which make it suitable for packaging food. If the addition of the anti-bacterial compound is limited so as not to damage the desired properties of the film, it could fail to produce a sufficient effectiveness in repelling bacteria.